CALL Statement
... Subroutine subprograms have many features in common with function subprograms: They are program units designed to perform particular tasks under the control of some other program unit. The have the same basic form: each consists of a heading, a specification part, an execution part, and an END state ...
... Subroutine subprograms have many features in common with function subprograms: They are program units designed to perform particular tasks under the control of some other program unit. The have the same basic form: each consists of a heading, a specification part, an execution part, and an END state ...
Course\FOS\FOS Unit-1 2014
... There is no universally accepted definition of what is part of the OS and what is not. A simple view point is that everything a vendor ships when you order "the OS" should be considered. The memory requirements and features included, however, vary (differs) greatly across different OSs. A more commo ...
... There is no universally accepted definition of what is part of the OS and what is not. A simple view point is that everything a vendor ships when you order "the OS" should be considered. The memory requirements and features included, however, vary (differs) greatly across different OSs. A more commo ...
Malware defenses (cont)
... • systrace only forwards monitored sys-calls to monitor (efficiency) • systrace resolves sym-links and replaces sys-call path arguments by full path to target • When app calls execve, monitor loads new policy file ...
... • systrace only forwards monitored sys-calls to monitor (efficiency) • systrace resolves sym-links and replaces sys-call path arguments by full path to target • When app calls execve, monitor loads new policy file ...
Components of a Linux System
... Its history has been one of collaboration by many users from all around the world, corresponding almost exclusively over the Internet ...
... Its history has been one of collaboration by many users from all around the world, corresponding almost exclusively over the Internet ...
Chapter 1 Slides
... A regular modem uses a phone line and can transfer data in a speed up to 56,000 bps (bits per second). A DSL (digital subscriber line) also uses a phone line and can transfer data in a speed 20 times faster than a regular modem. A cable modem uses the TV cable line maintained by the cable company. A ...
... A regular modem uses a phone line and can transfer data in a speed up to 56,000 bps (bits per second). A DSL (digital subscriber line) also uses a phone line and can transfer data in a speed 20 times faster than a regular modem. A cable modem uses the TV cable line maintained by the cable company. A ...
Operating Systems Lab.
... An operating system's le system structure is its most basic level of organization. Almost all of the ways an operating system interacts with its users, applications, and security model are dependent upon the way it stores its les on a storage device. A file system can be seen in terms of two differe ...
... An operating system's le system structure is its most basic level of organization. Almost all of the ways an operating system interacts with its users, applications, and security model are dependent upon the way it stores its les on a storage device. A file system can be seen in terms of two differe ...
Module 4: Processes
... Useful and Important Concept: Process = program in execution A process is not the same as a program. Program is a passive entity, whereas process is active. Process consists of an executable program, associated data, and execution context. Modern (multiprogramming) operating systems are structured a ...
... Useful and Important Concept: Process = program in execution A process is not the same as a program. Program is a passive entity, whereas process is active. Process consists of an executable program, associated data, and execution context. Modern (multiprogramming) operating systems are structured a ...
Linux Pres1 - Parent Directory
... The kernel is the core program that runs programs and manages Hardware devices and mostly written in “C”. Allocates the system resources, scheduling of task and memory management. 2. SHELL – interface between user and kernel The Shell provides an interface for the user. It receives commands from the ...
... The kernel is the core program that runs programs and manages Hardware devices and mostly written in “C”. Allocates the system resources, scheduling of task and memory management. 2. SHELL – interface between user and kernel The Shell provides an interface for the user. It receives commands from the ...
Unix File System
... Ext2fs uses allocation policies designed to place logically adjacent blocks of a file into physically adjacent blocks on disk, so that it can submit an I/O request for several disk blocks as a single operation. ...
... Ext2fs uses allocation policies designed to place logically adjacent blocks of a file into physically adjacent blocks on disk, so that it can submit an I/O request for several disk blocks as a single operation. ...
Operating-System Structures
... Programming interface to the services provided by the OS Typically written in a high-level language (C or C++) Mostly accessed by programs via a high-level Application ...
... Programming interface to the services provided by the OS Typically written in a high-level language (C or C++) Mostly accessed by programs via a high-level Application ...
Programming with Java
... The difference between the way Java and other programming languages worked was revolutionary. Code in other languages is first translated by a compiler into instructions for a specific type of computer. The Java compiler instead turns code into something called Bytecode, which is then interpreted by ...
... The difference between the way Java and other programming languages worked was revolutionary. Code in other languages is first translated by a compiler into instructions for a specific type of computer. The Java compiler instead turns code into something called Bytecode, which is then interpreted by ...
What is an Operating System?
... management must be provided. – A mechanism for concurrent execution, which requires CPU scheduling schemes. – Mechanisms for job synchronization and communication to ensure orderly execution. – A mechanism to avoid deadlock - a job waiting for another job forever. ...
... management must be provided. – A mechanism for concurrent execution, which requires CPU scheduling schemes. – Mechanisms for job synchronization and communication to ensure orderly execution. – A mechanism to avoid deadlock - a job waiting for another job forever. ...
Migration
... dependent on a prior (or perhaps first) host for these services. Checkpointing and recovery: A process's state to be saved to a file (much like a persistent object) and then a new process to be created (restored) based on this checkpoint file. This checkpoint file contains all of the "goods" includi ...
... dependent on a prior (or perhaps first) host for these services. Checkpointing and recovery: A process's state to be saved to a file (much like a persistent object) and then a new process to be created (restored) based on this checkpoint file. This checkpoint file contains all of the "goods" includi ...
CS 345 - Programming Languages
... create empty pq s insert each element from array into s remove elts in decreasing order and place in array end slide 12 ...
... create empty pq s insert each element from array into s remove elts in decreasing order and place in array end slide 12 ...
Memory manager
... After reading this chapter, the reader should be able to: Define the purpose and functions of an operating system. Understand the components of an operating system. Understand the concept of virtual memory. Understand the concept of deadlock and starvation. ...
... After reading this chapter, the reader should be able to: Define the purpose and functions of an operating system. Understand the components of an operating system. Understand the concept of virtual memory. Understand the concept of deadlock and starvation. ...
File System Maintenance (continued)
... • A file can be found by using the find command: – atime for last accessed time – ctime for last changed time – mtime for last modification time – name for the filename, including the use of wildcard searches ...
... • A file can be found by using the find command: – atime for last accessed time – ctime for last changed time – mtime for last modification time – name for the filename, including the use of wildcard searches ...
Handling Errors with Exception (in Java)
... The finally block gives a device for cleaning up the state of the method before allowing control to a different part of the program finally { if (out != null) { System.out.println(“closing PrintWriter"); out.close(); } else { System.out.println("PrintWriter not open"); } } ...
... The finally block gives a device for cleaning up the state of the method before allowing control to a different part of the program finally { if (out != null) { System.out.println(“closing PrintWriter"); out.close(); } else { System.out.println("PrintWriter not open"); } } ...
Migration
... dependent on a prior (or perhaps first) host for these services. Checkpointing and recovery: A process's state to be saved to a file (much like a persistent object) and then a new process to be created (restored) based on this checkpoint file. This checkpoint file contains all of the "goods" includi ...
... dependent on a prior (or perhaps first) host for these services. Checkpointing and recovery: A process's state to be saved to a file (much like a persistent object) and then a new process to be created (restored) based on this checkpoint file. This checkpoint file contains all of the "goods" includi ...
The Macintosh File System (continued)
... • Must be a way to write digital information onto disk, track it, update it, and recall it • OS typically groups disk sectors in some logical way, creates a record of this structure, and builds a directory to track the type of data stored in each file ...
... • Must be a way to write digital information onto disk, track it, update it, and recall it • OS typically groups disk sectors in some logical way, creates a record of this structure, and builds a directory to track the type of data stored in each file ...
PPT
... Programming interface to the services provided by the OS Typically written in a high-level language (C or C++) Mostly accessed by programs via a high-level Application ...
... Programming interface to the services provided by the OS Typically written in a high-level language (C or C++) Mostly accessed by programs via a high-level Application ...
Computer Network and Infrastructure
... A program in execution An instance of a program running on a computer The entity that can be assigned to and executed on a processor A unit of activity characterized by a single sequential thread of execution, a current state, and an associated set of system resources ...
... A program in execution An instance of a program running on a computer The entity that can be assigned to and executed on a processor A unit of activity characterized by a single sequential thread of execution, a current state, and an associated set of system resources ...
Implementing Processes, Threads, and Resources
... • MS-DOS - written to provide the most functionality in the least space – not divided into modules – Although MS-DOS has some structures, its interfaces and levels of functionality are not well separated. • application programs are able to access BIOS routines directly (bypassing DOS). ...
... • MS-DOS - written to provide the most functionality in the least space – not divided into modules – Although MS-DOS has some structures, its interfaces and levels of functionality are not well separated. • application programs are able to access BIOS routines directly (bypassing DOS). ...
Module 3: Operating
... I/O operations – since user programs cannot execute I/O operations directly, the operating system must provide some means to perform I/O - system calls and API. File-system manipulation – program capability to read, write, create, and delete files Communications – exchange of information between pro ...
... I/O operations – since user programs cannot execute I/O operations directly, the operating system must provide some means to perform I/O - system calls and API. File-system manipulation – program capability to read, write, create, and delete files Communications – exchange of information between pro ...
Library (computing)
In computer science, a library is a collection of non-volatile resources used by computer programs, often to develop software. These may include configuration data, documentation, help data, message templates, pre-written code and subroutines, classes, values or type specifications. In IBM's OS/360 and its successors they are referred to as partitioned data sets.In computer science, a library is a collection of implementations of behavior, written in terms of a language, that has a well-defined interface by which the behavior is invoked. This means that as long as a higher level program uses a library to make system calls, it does not need to be re-written to implement those system calls over and over again. In addition, the behavior is provided for reuse by multiple independent programs. A program invokes the library-provided behavior via a mechanism of the language. For example, in a simple imperative language such as C, the behavior in a library is invoked by using C's normal function-call. What distinguishes the call as being to a library, versus being to another function in the same program, is the way that the code is organized in the system. Library code is organized in such a way that it can be used by multiple programs that have no connection to each other, while code that is part of a program is organized to only be used within that one program. This distinction can gain a hierarchical notion when a program grows large, such as a multi-million-line program. In that case, there may be internal libraries that are reused by independent sub-portions of the large program. The distinguishing feature is that a library is organized for the purposes of being reused by independent programs or sub-programs, and the user only needs to know the interface, and not the internal details of the library.The value of a library is the reuse of the behavior. When a program invokes a library, it gains the behavior implemented inside that library without having to implement that behavior itself. Libraries encourage the sharing of code in a modular fashion, and ease the distribution of the code. The behavior implemented by a library can be connected to the invoking program at different program lifecycle phases. If the code of the library is accessed during the build of the invoking program, then the library is called a static library. An alternative is to build the executable of the invoking program and distribute that, independently from the library implementation. The library behavior is connected after the executable has been invoked to be executed, either as part of the process of starting the execution, or in the middle of execution. In this case the library is called a dynamic library. A dynamic library can be loaded and linked as part of preparing a program for execution, by the linker. Alternatively, in the middle of execution, an application may explicitly request that a module be loaded.Most compiled languages have a standard library although programmers can also create their own custom libraries. Most modern software systems provide libraries that implement the majority of system services. Such libraries have commoditized the services which a modern application requires. As such, most code used by modern applications is provided in these system libraries.